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Biomedical subjects

M A Thomas

Publications and source records attributed to M A Thomas.

At least 55 records · Page 3Linked to original sources
PubMed1998

Surgical removal of extensive peripapillary choroidal neovascularization associated with presumed ocular histoplasmosis syndrome.

OBJECTIVE: This study aimed to report the visual outcome of surgical removal of extensive peripapillary choroidal neovascularization (CNV) due to presumed ocular histoplasmosis syndrome (POHS). DESIGN: Retrospective review of the records of all patients seen at the Barnes Retina Institute who underwent surgical removal of extensive peripapillary CNV associated with POHS and who had at least 12 months of follow-up. PARTICIPANTS: Seventeen consecutive eyes (in 14 patients) undergoing surgical removal of extensive peripapillary CNV associated with POHS were studied. INTERVENTION: Pars plana vitrectomy and surgical removal of CNV were performed. MAIN OUTCOME MEASUREMENTS: Best-corrected Snellen visual acuity, funduscopic examination, and intravenous fluorescein angiography were obtained before surgery and at regular intervals after surgery. RESULTS: In 14 of 17 eyes, the peripapillary CNV was subfoveal, and in 3 eyes, it was extrafoveal. All three eyes with extrafoveal CNV were not eligible for laser treatment according to Macular Photocoagulation Study guidelines because treatment would have spared less than 1.5 contiguous clock-hours of retina temporal to the optic disc. Follow-up ranged from 17 to 57 months, with a median of 32 months. In eyes with subfoveal CNV, best-corrected preoperative Snellen visual acuity ranged from 20/25 to counting fingers at 2 feet with a median of 20/200, and best-corrected final Snellen visual acuity ranged from 20/25 to 20/200 with a median of 20/40. In 7 (50%) of 14 eyes, a final Snellen acuity of 20/40 or better was achieved, and in all cases except 1, visual acuity improved or did not change with surgery. In the three eyes with extrafoveal CNV, best-corrected preoperative Snellen visual acuity ranged from 20/20 to 20/400 with a median of 20/200, and best-corrected final Snellen visual acuity was 20/20 in all cases. In addition, visual acuity improved with surgery. CONCLUSIONS: The data from this small retrospective study suggest that surgical removal may provide visual benefit in selected cases of extensive peripapillary CNV due to POHS.

Adolescent↗
PubMed1998

Present indications for removal of choroidal neovascular membranes.

Subretinal choroidal neovascularization is an important cause of visual loss in adults. Removal of choroidal neovascular membranes using relatively new techniques of subretinal surgery holds promise for improving or stabilizing vision in some patients. A number of factors have been proposed that may affect the outcome of subretinal surgery for choroidal neovascularization, including the degree of involvement of Bruch's membrane, the location of the neovascular complex relative to the retinal pigment epithelium and Bruch's membrane, the location of the ingrowth site, and the etiology of the membranes. Although the surgical techniques are relatively refined, the indications for removal of choroidal neovascular membranes are still under investigation. This article reviews the recent and past literature and summarizes the authors' specific recommendations regarding present indications for removal of choroidal neovascular membranes.

Choroid↗
PubMed1998

Cerebral 1H MR spectroscopy and neuropsychologic status of patients with hepatic encephalopathy.

OBJECTIVE: Our objective was to assess the metabolite levels (myo-inositol [ml], choline [Cho], creatine [Cr], glutamate or glutamine [Glx], and N-acetyl-L-aspartate [NAA]) visible on 1H MR spectroscopy in patients with subclinical and mild hepatic encephalopathy before and after liver transplantation and to correlate these data with the results of neuropsychiatric tests and related clinical findings. SUBJECTS AND METHODS: A stimulated-echo sequence was used to localize a single voxel in the parietal region. Seventeen patients and 13 healthy volunteers were investigated. Nine of the 17 patients also were investigated after liver transplantation. A battery of neuropsychologic tests also was administered to patients to assess frontal, memory, and motor functions. RESULTS: Before liver transplantation, significant reductions in mI:Cr (51%) and Cho:Cr (11%) and a significant increase in Glx:Cr (20%) were observed in patients compared with the respective ratios in healthy subjects. Patients also were significantly impaired on neuropsychologic tests measuring frontal and motor performance, but not memory. Impairment on the frontal index showed a significant correlation with mI:Cr levels; likewise, performance on the motor index showed a significant correlation with serum ammonia levels before transplantation. MR spectroscopy after liver transplantation showed changes in the metabolite ratios compared with the pretransplantation status. Even though the Glx:Cr ratios decreased after transplantation, the mI:Cr ratio remained lower than those of healthy subjects. CONCLUSION: The relationship of changes in the metabolite ratios recorded from a voxel in the posteromedial parietal lobe to the neuropsychologic findings before and after liver transplantation is a major finding.

Adult↗
PubMed1998

Proton MR spectroscopy in Lesch-Nyhan disease.

In vivo proton spectra for four patients with Lesch-Nyhan disease and four control subjects matched for age and sex were acquired from voxels (1.5 x 1.5 x 1.5 cm3) placed in the prefrontal cortex and striatum. The patients with Lesch-Nyhan disease had decreased metabolites, especially N-acetylaspartate and glutamate/glutamine, only in the prefrontal cortex as compared with the control group. These findings suggest axonal loss in the prefrontal area of this population. The cortical glutamate/glutamine peak decrement does not confirm cytopathologic studies of Lesch-Nyhan disease and deserves further investigation.

Adolescent↗
PubMed1997

Surgical removal of subfoveal choroidal neovascularization in presumed ocular histoplasmosis: stability of early visual results.

PURPOSE: The authors assess the stability of visual acuity outcomes after the surgical removal of subfoveal choroidal neovascularization in a large series of patients with presumed ocular histoplasmosis syndrome (POHS). METHODS: A retrospective study of 117 consecutive patients undergoing vitrectomy between February 1990 and December 1994 was performed. All patients underwent the surgical removal of subfoveal choroidal neovascularization due to POHS and had at least 3 months of follow-up. Postoperative Snellen visual acuity was the primary study endpoint. RESULTS: With a median follow-up of 13 months (range, 3-46 months), 35% of patients had postoperative visual acuity of 20/40 or better, and 40% had improvement of three or more Snellen lines after surgery. In a subset of 54 eyes followed for at least 1 year, 91% showed stable or improved vision between the 3- and 12-month time points, and 85% showed stable or improved vision between 3 months and final visit. CONCLUSION: Follow-up of a large number of patients appears to confirm initially encouraging results and to suggest stability of beneficial effect after the surgical removal of subfoveal choroidal neovascularization in POHS.

Adolescent↗
PubMed1997

Endosalpingiosis and chronic pelvic pain.

OBJECTIVE: To show that endosalpingiosis (ES) is a frequently underdiagnosed or misdiagnosed entity in women thought to have endometriosis (EM) on initial pathologic review and that ES alone may be an independent cause of pelvic pain. STUDY DESIGN: A retro-spective review of pathology records from gynecologic cases from June 1992 to November 1994 revealed 37 cases of EM and 5 cases of ES. These cases were reviewed by a single pathologist (J.M.), who assigned a final diagnosis. Preoperative diagnosis or symptoms that led to surgery were compared to the initial and final pathologic diagnoses. RESULTS: Of the 37 cases with the initial diagnosis of EM, 64.9% had EM only (group I), 18.9% had both EM and ES (group II), and 16.2% had ES alone (group III). Of the five patients with an initial diagnosis of ES, 80% had ES (group IV), while 20% had both ES and EM (group V). In patients who had ES as their final diagnosis (group III and IV), 70% had chronic pelvic pain or presumed endometriosis as a preoperative diagnosis. This was similar to the 53.1% of patients with a final diagnosis of EM who had the same preoperative diagnosis. CONCLUSION: We conclude that ES is more common than once thought. Furthermore, when an initial diagnosis of EM is made, further review may reveal that many of these cases are a combination of both EM and ES, while still others may be ES alone. ES, which has been long been thought to be clinically insignificant, could be a source of pelvic pain.

Diagnosis, Differential↗
PubMed1997

Submacular surgery.

Modern vitreoretinal surgery is now one of the most effective tools for treating posterior segment diseases. In the last several years, there has been a surge of interest in submacular surgery which allows removal of submacular choroidal neovascular membranes and haematomas. Various aspects of this rapidly emerging modality of surgery are discussed in this review.

Choroid↗
PubMed1996

Involvement of integrins alpha v beta 3 and alpha v beta 5 in ocular neovascular diseases.

Angiogenesis underlies the majority of eye diseases that result in catastrophic loss of vision. Recent evidence has implicated the integrins alpha v beta 3 and alpha v beta 5 in the angiogenic process. We examined the expression of alpha v beta 3 and alpha v beta 5 in neovascular ocular tissue from patients with subretinal neovascularization from age-related macular degeneration or the presumed ocular histoplasmosis syndrome or retinal neovascularization from proliferative diabetic retinopathy (PDR). Only alpha v beta 3 was observed on blood vessels in ocular tissues with active neovascularization from patients with age-related macular degeneration or presumed ocular histoplasmosis, whereas both alpha v beta 3 and alpha v beta 5 were present on vascular cells in tissues from patients with PDR. Since we observed both integrins on vascular cells from tissues of patients with retinal neovascularization from PDR, we examined the effects of a systemically administered cyclic peptide antagonist of alpha v beta 3 and alpha v beta 5 on retinal angiogenesis in a murine model. This antagonist specifically blocked new blood vessel formation with no effect on established vessels. These results not only reinforce the concept that retinal and subretinal neovascular diseases are distinct pathological processes, but that antagonists of alpha v beta 3 and/or alpha v beta 5 may be effective in treating individuals with blinding eye disease associated with angiogenesis.

Animals↗
PubMed1996

Clinicopathologic correlation of submacular membranectomy with retention of good vision in a patient with age-related macular degeneration.

We present the clinicopathologic features of the eye of a patient with age-related macular degeneration who underwent submacular membranectomy and had retention of good visual acuity for almost 4 years despite recurrent choroidal neovascularization treated with krypton laser photocoagulation and mild expansion of the laser lesion with time. Histopathologic study of the surgically removed membrane from the right eye disclosed a thin fibrovascular membrane lined by retinal pigment epithelium on one surface. Microscopic examination of the right eye obtained post mortem disclosed a 2.75-mm (horizontal) x 2.1-mm (vertical) retinal pigment epithelium defect with overlying photoreceptor cell atrophy centered on the temporal parafoveal area, and a 0.6 x 0.1-mm subretinal pigment epithelium fibrovascular membrane with an area of retinal pigment epithelial hyperplasia and vascularization from the retina 0.4 mm temporal to the fovea. Basal laminar deposit was present in the region of the fovea and nasal parafoveal area.

Aged↗
PubMed1996

Success of donor oocyte in in vitro fertilization-embryo transfer in recipients with and without premature ovarian failure.

OBJECTIVE: To compare the effectiveness of donor oocyte in IVF-ET in patients with premature ovarian failure (POF) versus those (non-POF) with other indications for donor oocyte IVF-ET. DESIGN: Retrospective comparative clinical study. SETTING: University-based IVF-ET facility. PATIENTS: Eighty-six donor oocyte IVF-ET cycles from 32 POF patients (39 cycles) and 38 non-POF patients (47 cycles). INTERVENTIONS: Fertile oocyte donors, age 19 to 38 years, were given luteal phase GnRH agonist, gonadotropins, and HCG. Recipients were given transdermal 17 beta-E2 and P in oil. MAIN OUTCOME MEASURES: Donor and recipient age, characteristics of controlled ovarian hyperstimulation, oocytes retrieved, embryos frozen and transferred, and percentage with male factor infertility, fertilization rate, implantation rate, and clinical pregnancy rate (PR) per cycle and per transfer. RESULTS: Given limitations of sample size, there were no detectable differences in clinical PR per cycle and per transfer, fertilization rate, and implantation rate between POF and non-POF groups despite recognizable differences in recipient age and degree of male factor infertility. CONCLUSIONS: Donor oocyte IVF-ET success rates were not different in patients with and without POF. Age-related changes in oocyte quality, rather than uterine senescence, is a major factor for the age-related decline in fertility.

Adult↗
PubMed1996

Managing recurrent neovascularization after subfoveal surgery in presumed ocular histoplasmosis syndrome.

PURPOSE: To report the authors' experience with recurrent neovascularization after subfoveal surgery in the presumed ocular histoplasmosis syndrome (POHS). METHODS: One-hundred seventeen patients with POHS and subfoveal choroidal neovascularization were followed a median of 13 months after submacular surgery. RESULTS: Recurrent neovascularization developed in 51 eyes (44%). The median time to recurrence was 3 months (range, 0.5-28 months). Recurrence location was extrafoveal in 16%, juxtafoveal in 18%, and subfoveal in 66%. Sixteen eyes were treated with laser photocoagulation, 17 eyes underwent repeat submacular surgery, and 18 eyes were observed. The visual outcome for patients with recurrences amenable to laser was better than that for patients who were observed or who underwent surgery. CONCLUSION: Recurrent neovascularization after surgery is common; prompt recognition may allow laser photocoagulation.

Choroid↗
PubMed1996

Recurrent graft pain following renal autotransplantation for loin pain haematuria syndrome.

OBJECTIVE: To review retrospectively the Perth experience of autotransplantation for loin pain haematuria syndrome and identify possible factors associated with its failure. PATIENTS AND METHODS: The medical records of 11 women patients (median age 42 years, range 29-48) who had 12 autotransplantations were reviewed. All patients were then interviewed and asked whether they considered the operation a success. RESULTS: All patients initially had complete relief of symptoms. Three patients who had four transplants are still symptom-free with a follow-up of 24-46 months. Five patients have had partial relief with marked variability in their patterns of recurrent pain. Three patient have symptoms as severe as those before operation. One kidney was lost because of acute thrombosis and another developed a urinoma. No patient had deterioration in renal function. CONCLUSION: Renal autotransplantation is a treatment option of last resort, with acceptable morbidity in patients with intractable, functionally disabling renal pain, but three-quarters of these patients may develop recurrent pain in the transplant site. A current or past history of depression or absence of haematuria may represent risk factors for a poor post-operative prognosis. Treatment failure is predictable by a poor response to sympathetic neurolytic block.

Adult↗
PubMed1996

The surgical removal of subfoveal choroidal neovascularization. Ingrowth site as a predictor of visual outcome.

PURPOSE: The authors determine the significance of location of the ingrowth site of subfoveal choroidal neovascularization (CNV) as a preoperative indicator of postsurgical visual acuity. DESIGN: A retrospective review is given of preoperative fluorescein angiograms and color fundus photographs for 84 eyes with subfoveal CNV due to the following etiologies: presumed ocular histoplasmosis syndrome (POHS) = 67 eyes; multifocal choroiditis = 9 eyes; not identifiable. If identifiable, the ingrowth site was further classified as extrafoveal, juxtafoveal, or subfoveal. Correlations between CNV ingrowth site location and postoperative visual acuity were made. RESULTS: The ingrowth site for subfoveal CNV was identifiable preoperatively in 60 eyes (71%). Of 31 eyes with an extrafoveal ingrowth site, 18 (60%) had a final visual acuity of 20/40 or better. Of 12 eyes with a juxtafoveal ingrowth site and 18 eyes with a subfoveal ingrowth site, only 2 (7%) had a final visual acuity of 20/40 or better. If the ingrowth site was not identifiable or identifiable and subfoveal in location (N = 42), 76% of eyes had a final visual acuity of 20/200 or worse. CONCLUSION: The ingrowth site of subfoveal CNV can be identified in the majority of eyes with POHS, multifocal choroiditis, or idiopathic membranes. A significant number of subfoveal CNV will have an extrafoveal ingrowth site. Eyes with an extrafoveal ingrowth site have a favorable visual prognosis after the surgical removal of the CNV. If the ingrowth site is subfoveal or not identifiable, the visual prognosis after surgery is guarded.

Adult↗
PubMed1996

Rhegmatogenous retinal detachment in eyes with uveal melanoma.

PURPOSE: To describe the clinical features, surgical management, and outcome of patients with uveal melanoma who presented with or later developed a rhegmatogenous retinal detachment. METHODS: We retrospectively identified four patients who presented with uveal melanoma and rhegmatogenous retinal detachment simultaneously and six patients in whom a rhegmatogenous retinal detachment developed 11-100 months (mean, 44.8 months) after radiotherapy for a choroidal melanoma. RESULTS: All four patients with simultaneous presentation of uveal melanoma and retinal detachment underwent successful retinal detachment repair (cases 1 and 4, scleral buckle; case 2, pars plana vitrectomy, and case 3, pneumatic retinoplexy). Rhegmatogenous retinal detachment occurring after proton beam or plaque radiotherapy of uveal melanoma was repaired successfully in five of six patients with scleral buckling alone or in combination with pars plana vitrectomy. In the short follow-up period of this study, we did not observe tumor recurrence either before or after retinal detachment repair. CONCLUSION: Rhegmatogenous retinal detachment associated with uveal melanoma may be treated successfully using conventional retinal surgical techniques. The benefits of retinal detachment repair must be weighed against any theoretical increased risk of extra-scleral extension of the melanoma. Long-term follow-up evaluation will be required to determine the safety of various retinal detachment repair techniques in these eyes.

Aged↗
PubMed1996

What is a human resources strategy?

Attempts to provide a practical framework in which practitioners may develop human resources (HR) strategies in line with their organizations' corporate planning processes. Proposes a four-step approach involving: development of a strategic framework; generating of HR mission statement; application of analysis; and making strategic planning decision between HR options. Outlines a four-dimensional structural focus comprising culture, organization, people and systems. Concludes with a discussion of characteristic of ¿good¿ strategic objectives.

Evaluation Studies as Topic↗